This invention relates to a fuel injection pump for internal combustion engines, and more particularly to an improvement on a fuel injection pump with preparatory chambers for metering an amount of fuel.
In a fuel injection pump, in order to improve metering precision of an amount of fuel from an electromagnetic valve for metering, and to expand injection timing control range, it is necessary to supply metered fuel from the electromagnetic valve into pump chambers through metering preparatory chambers. Such a fuel injection pump with preparatory chambers is disclosed in prior U.S. patent application Ser. No. 467,302 still pending filed by Yoshiya Takano and Yoshikazu Hoshi on Feb. 17, 1983 (the corresponding European patent application Ser. No. 83101476.6 filed on Feb. 16, 1983). The fuel injection pump comprises a rotor driven by the engine and a housing accomodating the rotor. In the rotor, two pump chambers are formed, and the housing is provided with the preparatory chambers and solenoid valves for metering the fuel to be fed to the chambers. In the rotor and the housing various fuel passages and switching valves are formed, and fuel from a fuel source is delivered to the engine through the solenoid valves, the preparatory chambers, the pump chambers and the various fuel passages and switching valves.
In this fuel injection pump, the various passages and switching valves are relatively complicated and more simple construction is desirable.
An object of the invention, therefore, is to provide a fuel injection pump which is simpler in construction.
Another object of the invention is to provide a fuel injection pump which is compact and stable in construction.
Briefly stated, the present invention resides in that solenoid valves for metering and supplying fuel and metering preparatory chambers are arranged such that fuel from said solenoid valves enters directly into said metering preparatory chamber.
The other features, advantageous effects, etc. of the present invention will be understood by description of an embodiment referring to the drawings.